1. Technical Field
The present invention relates to engine ignition systems. More particularly, it relates to a method of controlling ignition timing.
2. Discussion
The prior art includes a variety of conventional methods for detecting and using ionization current in a combustion chamber of an internal combustion engine. However, each of the various conventional systems suffers from a great variety of deficiencies. For example, prior art ionization current detection circuits are generally too slow and generate a current signal with low signal-to-noise ratio.
The individual cylinder air to fuel ratio of an internal combustion engine varies due to the fact that the intake manifold cannot distribute airflow into the individual cylinders evenly, even when the global air to fuel ratio is maintained at stoich. The difference in air to fuel ratio between individual cylinders affects engine emission, fuel economy, idle stability, vehicle Noise, Vibration and Handling, etc.